JP2003152309A - Method of manufacturing double-sided flexible circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing double-sided flexible circuit board by which an insulating base material can be worked, continuity holes required for the formation of via holes and double-sided exposed wiring can be formed, and the contour forming of a product can be performed. SOLUTION: In this method of manufacturing double-sided flexible circuit board, holes and grooves are simultaneously formed at into the insulating base material 2 by laser beam machining, plasma etching, or resin etching by using at least one conductor layer of a both-sided copper-clad board as a mask and the holes and grooves are used for forming continuity holes and the contour a circuit board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a double-sided flexible circuit board, and more particularly, to a conductive hole necessary for processing an insulating base material and forming a via hole by laser processing, plasma etching method or resin etching method. The present invention relates to a method for manufacturing a double-sided flexible circuit board that enables formation, formation of exposed wiring on both sides, and external processing of a product.

[0002]

2. Description of the Related Art Conventionally, in a manufacturing process of a double-sided flexible circuit board, a method using an NC drill or a metal mold has been widely adopted for making a hole for conduction and for processing the outer shape of the circuit board. . However, with the recent increase in density and miniaturization of wiring boards, a copper foil having a thin copper foil as a conductor layer of a double-sided copper clad board has come to be used. When such a copper foil with a thin thickness is used for punching and external processing with a die, there is a problem that wrinkles and traces are likely to be formed on the substrate, and cracks are formed especially on the thin copper foil. .

Further, in recent years, the demand for double-sided exposed wiring for fine patterns has been growing, but a double-sided flexible circuit board having a double-sided exposed wiring structure using an NC drill or a mold is not suitable for fine processing. Not only is it difficult, but the process is complicated and the yield is poor.

In recent years, laser processing using a carbon dioxide gas laser, a YAG laser, an excimer laser, etc., a plasma etching method, and a wet etching method have been adopted to provide an opening for double-sided exposed wiring. In both cases, since the openings for the double-sided exposed wiring are provided after the wiring is formed, the double-sided exposed wiring portion having no insulator on both sides of the conductor is extremely fragile, resulting in a decrease in yield. In addition, the opening by laser processing has a drawback that the productivity deteriorates as the processing area within a unit area increases.

From such a background, it has been difficult to inexpensively and stably manufacture a double-sided flexible circuit board having fine double-sided exposed wiring.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a method for suitably solving the above-mentioned conventional problems, and in a method for manufacturing a double-sided flexible circuit board, at least a double-sided copper-clad board is used. Using one conductor layer as a mask, the holes and grooves of the insulating base material are processed at the same time by laser processing, plasma etching method, and resin etching method, and the holes and grooves are used as conduction holes, openings for double-sided exposed wiring, and circuit board outline. A method of manufacturing a double-sided flexible circuit board, which is characterized by being applied to processing, is adopted.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be further described below with reference to the illustrated embodiments. FIG. 1 shows a manufacturing process diagram of a double-sided flexible circuit board according to an embodiment of the present invention. When manufacturing a double-sided flexible circuit board, as shown in FIG. A double-sided copper-clad board having 1, an insulating base material 2 and a second conductor layer 3 is used.

Next, as shown in FIG. 2B, the first conductor layer 1 is subjected to etching processing, and laser processing, plasma etching method, and wet etching method are used for conducting holes, outer shape processing, and opening portions of both-side exposed wiring. A mask layer 4 for forming is formed. This mask layer 4 is formed in the shape of a wiring pattern.

Thereafter, as shown in FIG. 3C, the insulating base material 2 is processed by the laser processing, the plasma etching method, and the wet etching method using the mask layer 4, and the conduction hole 5 and the product outer shape processing opening. The portion 6 and the opening 7 of the double-sided exposed wiring are formed.

Next, as shown in FIG. 4 (4), a via hole 9 is formed by conducting a conductive treatment to form a plating layer 8.
To form. Then, as shown in FIG. 5 (5), etching processing is performed to form the wiring pattern 10 on the first surface. Finally, as shown in (6) of FIG.
A wiring pattern 11 is formed by subjecting the wiring pattern to etching to form a wiring pattern 11, and a double-sided flexible circuit board having a via hole connection, double-sided exposed wiring, and an outer shape processing groove 12 provided with a connecting portion is obtained.

[0011]

In the double-sided flexible circuit board according to the present invention, the hole for conduction, the outer shape processing and the opening of the both-side exposed wiring can be simultaneously formed by using the laser processing, the plasma etching method and the wet etching method.

Further, it is possible to process the outer shape of a thin, small-sized flexible circuit board which is difficult to process with a die. It is possible to arbitrarily remove or leave the conductor layers on both sides of the connecting portion at the time of this outer shape processing, so that necessary strength can be secured.

Therefore, an inexpensive double-sided flexible circuit board, which has been difficult by the conventional method for manufacturing a double-sided flexible circuit board, can be provided inexpensively and stably.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a double-sided flexible circuit board showing an embodiment of the present invention.

[Explanation of symbols]

1 First conductor layer 2 Insulating base material 3 Second conductor layer 4 Mask layer 5 Conduction hole 6 openings 7 openings 8 plating layer 9 Beer hall 10 wiring patterns 11 wiring pattern 12 External processing groove

Claims (3)

[Claims] 1. A method of manufacturing a double-sided flexible circuit board, wherein at least one conductor layer of a double-sided copper-clad board is used as a mask for laser processing, plasma etching or resin etching to simultaneously form holes and grooves in an insulating base material. Then
A method for manufacturing a double-sided flexible circuit board, characterized in that the holes and grooves are applied to the hole for conduction and the outer shape processing of the circuit board. 2. The method for producing a double-sided flexible circuit board according to claim 1, wherein the double-sided exposed wiring is formed after processing the insulating base material by processing the conductor layer on the surface opposite to the conductor layer. 3. The method for manufacturing a double-sided flexible circuit board according to claim 1, wherein the conductor layers on both sides of the connecting portion provided on the insulating base material of the groove for contour processing are removed.